“Τρίας is either the number Three, or a triplet of similar objects, as in the phrase κασιγνήτων τριάς (Rost u. Palm’s Lexicon. s.v.) In this sense it is applied by Clement of Alexandria (Strom. IV. vii. 55) to the Triad of Christian graces, Faith, Hope, and Charity. As Gregory of Nazianzus says (Orat. xiii. p. 24) Τριὰς οὐ πραγμάτων ἀνίσων ἀπαρίθμησις, ἀλλ᾽ ἴσων καὶ ὁμοτίμων σύλληψις. The first instance of its application to the Three Persons in the one God is in Theophilus of Antioch (Ad Autol. ii. 15)” [†. c. 185] “Similarly the word Trinitas, in its proper force, means either the number Three or a triad. It is first applied to the mystery of the Three in One by Tertullian, who says that the Church ‘proprie et spiritualiter ipse est spiritus, in quo est Trinitas unius divinitatis, Pater, et Filius, et Spiritus Sanctus.’ De Pudicita 21.” [† c. 240] Archd. Cheetham. Dict. Christ. Biog. S.V.